President Obama will become the first sitting president to visit Hiroshima, 71 years after the United States dropped an atomic bomb on the city to end World War II.

When the US dropped an atomic bomb on the city of Hiroshima on Aug. 6, 1945, an estimated 140,000 Japanese citizens were killed, a city was leveled and Japan surrendered six days later. Mr. Obama will visit the Hiroshima memorial on May 27 to "honor the memory of all innocents who were lost during the war" as well as reaffirm America's commitment to "a world without nuclear weapons," White House Deputy National Security Advisor Ben Rhodes writes Tuesday.

The White House has made it clear that Obama will not offer an apology for the bombing, and Prime Minister Abe has said he does not expect one: simply a visit itself is enough.

"The prime minister of the world's only nation to have suffered atomic attacks, and the leader of the world's only nation to have used the atomic weapons at war together pay respects for the victims," Mr. Abe told reporters Tuesday. "I believe that would be a way to respond to the victims of the atomic bombings and the survivors who are still in pain."

Obama's visit is a "bold decision based on conscience and rationality," said Hiroshima Mayor Kazumi Matsui, and "a historic first step toward an international effort toward abolishing nuclear weapons," which he says should be an international goal.

"We are not asking for an apology," Sunao Tsuboi, 91, a survivor of the bombing, tells NHK national television. "All we want is to see him lay flowers at the peace park and lower his head in silence. This would be a first step toward abolishing nuclear weapons."

Between August 1945 to July 2005, Gallup periodically polled Americans' approval of the Hiroshima bombing.

A few days after the bombing in 1945, a Gallup poll found that 85 percent of Americans approved of the bombing while only 10 percent disapproved. In 1995, approval and disapproval registered at 59 and 35 percent respectively. And then in 2005, Gallup found that 57 percent of Americans approved and 38 percent disapproved.

Pew Research Center found that similar opinions still persist in 2015: 56 percent of Americans believe the bombing of Hiroshima and Nagasaki was justified, opposed to 34 percent who say the bombs were not justified.

And as for the Japanese pubic, the 1945 bombings are also seeming more unjustified as time moves on. In a Detroit Free Press study from 1991, 29 percent of Japanese though the atom bomb was justified. Today, only 14 percent of Japanese feel the same way.

Obama's historic visit, and Americans' increasing disapproval of the Hiroshima bombing, come at a time when Abe and fellow leaders of the Liberal Democratic Party seek to revise the country's strictly pacifist Constitution. Abe and his party are currently walking a line between repentance for past actions and concern about future vulnerabilities, as demonstrated by his lukewarm disapproval of nuclear weapons at last year's Hiroshima memorial speech and his recent apology to South Korean officials for the wartime forced-prostitution system of Korean "comfort women."

Abe's speech at the Hiroshima memorial last year was contentious because his administration was simultaneously pushing for bills in the Diet (Japan’s bicameral legislature) that would bolster the country’s Self-Defense Forces. A group of protestors criticized Abe's appearance at the memorial because of his recent policy proposals that they perceived as clearly "pro-war," reports the Japan Times.

"But Abe, a nationalist whose administration has overseen attempts to expand Japan's military power after decades of pacifism, had not previously offered an apology of his own" to South Korea on the matter, writes The Monitor's Molly Jackson. Abe's apology was not as strong as South Korea had hoped for he used the opportunity to insist, "we must not let our children, grandchildren, and even further generations to come, who have nothing to do with that war, be predestined to apologize."

And the Obama administration has made it clear that America is also done with apologizing.

"[Obama] will not revisit the decision to use the atomic bomb at the end of World War II," writes Mr. Rhodes. "Instead, he will offer a forward-looking vision focused on our shared future."